Torre de Pero Niño, Defensive tower in Llano, San Felices de Buelna, Spain

Torre de Pero Niño, also called Torre de la Aguilera, is a late 14th-century Gothic tower-house in the Llano district of San Felices de Buelna. It measures 14 metres long by 9 wide and about 11.50 metres high, with masonry walls 90 centimetres thick, thinner on the top floor. Its three floors stand 4.50, 4.30 and 2.70 metres high; the main east door sits under a pointed arch with large voussoirs.

The tower was built in the late 14th century by Alfonso Niño Laso de la Vega as a stronghold for the family living in the area. After Pero Niño died, a dispute over the inheritance divided his heirs for years and affected who controlled this fortification.

The tower takes its name from Admiral Pero Niño, a renowned medieval military commander whose deeds are preserved inside through historical objects and documents. His story continues to shape how people view this place and its importance to the region.

The tower stands in the Llano neighbourhood of San Felices de Buelna, in the municipality's west, and has housed a museum on Pero Niño's life and era since 12 January 2008. The entrance is on the eastern facade, under a pointed arch with large voussoirs. The three floors are reached by interior stairs; the walls are 90 cm thick, thinner on the top floor.

On the upper floor of the east and south facades, two round-arched openings differ from the pointed arches elsewhere; they led onto wooden cadalsos, galleries at the top of medieval towers. The support points of these structures can still be seen at the height of the third floor.